<div class="refentry" lang="en" xml:lang="en"><a id="glXSwapBuffers"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glXSwapBuffers — exchange front and back buffers</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table><tr><td><code class="funcdef">void <b class="fsfunc">glXSwapBuffers</b>(</code></td><td>Display *  </td><td><var class="pdparam">dpy</var>, </td></tr><tr><td> </td><td>GLXDrawable  </td><td><var class="pdparam">drawable</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>dpy</code></em></span></dt><dd><p>
                    Specifies the connection to the X server.
                </p></dd><dt><span class="term"><em class="parameter"><code>drawable</code></em></span></dt><dd><p>
                    Specifies the drawable whose buffers are to be swapped.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">glXSwapBuffers</code> promotes the contents of the back buffer of <em class="parameter"><code>drawable</code></em> to become
            the contents of the front buffer of <em class="parameter"><code>drawable</code></em>.
            The contents of the back buffer then become undefined.
            The update typically takes place during the vertical retrace of
            the monitor,
            rather than immediately after <code class="function">glXSwapBuffers</code> is called.
        </p><p>
            <code class="function">glXSwapBuffers</code> performs an implicit <a class="citerefentry" href="glFlush"><span class="citerefentry"><span class="refentrytitle">glFlush</span></span></a> before it returns.
            Subsequent OpenGL commands may be issued immediately after calling <code class="function">glXSwapBuffers</code>,
            but are not executed until the buffer exchange is completed.
        </p><p>
            If <em class="parameter"><code>drawable</code></em> was not created with respect to a double-buffered visual,
            <code class="function">glXSwapBuffers</code> has no effect,
            and no error is generated.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
            The contents of the back buffer become undefined after
            a swap. Note that this applies to pixel buffers as well as windows.
        </p><p>
            All GLX rendering contexts share the same notion of which are front buffers
            and which are back buffers.
            One consequence is that when multiple clients are rendering to the same
            double-buffered window,
            all of them should finish rendering before one of them issues the command
            to swap buffers.
            The clients are responsible for implementing this synchronization.
            Typically this is accomplished by executing <a class="citerefentry" href="glFinish"><span class="citerefentry"><span class="refentrytitle">glFinish</span></span></a> and then
            using a semaphore in shared memory to rendezvous before swapping.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GLXBadDrawable</code> is generated if <em class="parameter"><code>drawable</code></em> is not a valid GLX drawable.
        </p><p>
            <code class="constant">GLXBadCurrentWindow</code> is generated if <em class="parameter"><code>dpy</code></em> and <em class="parameter"><code>drawable</code></em> are
            respectively the display and drawable associated with the current
            context of the calling thread, and <em class="parameter"><code>drawable</code></em> identifies a window that
            is no longer valid.
        </p></div>
        {$pipelinestall}{$examples}
        <div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="glFlush"><span class="citerefentry"><span class="refentrytitle">glFlush</span></span></a>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><div id="Copyright"><h2>Copyright</h2><p>
            Copyright © 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <a class="ulink" href="https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/" target="_top">https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/</a>.
        </p></div></div></div>
